Geostationary Solar Eclipse Oct.3

From: Gerhard HOLTKAMP (grd.holtkamp@t-online.de)
Date: Wed Sep 28 2005 - 14:33:43 EDT

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    Hi everyone,
    
    on 3-OCT-05 while an annular eclipse of the Sun is visible in Europe and 
    Africa observers on the opposite side of the globe can see this eclipse in an 
    indirect way by looking at some geostationary satellites. GEOs close to 140.9 
    deg East will experience an annular eclipse at around 13:30 UTC. These 
    satellites can be observed under dark skies from Australia, New Zealand, East 
    Asia and Hawaii. The expected drop in brightness of the GEOs due to the 
    eclipse should be about mag 1.5 of which 1 mag happens during the final 8 
    minutes before annularity. (At the position of the GEOs in question the Moon 
    is further away and covers a smaller fraction of the Sun that it does for 
    observers on the other side of the globe - that's why the drop in magnitude 
    is not bigger.) 
    
    Here are six GEOs which will experience an annular eclipse (all times are 
    UTC):
    
    MBSAT		28184	144.1E	13:06 - 13:39 (annular from 13:21:24 - 13:22:31)
    SUPERB.C	24880	144.0E	13:06 - 13:39 (annular from 13:21:37 - 13:22:43)
    HIMARARI6	28622	140.4E	13:17 - 13:51 (annular from 13:32:21 - 13:34:52)
    BEIDOU1	26599	140.1E	13:18 - 13:51 (annular from 13:33:05 - 13:35:28)
    EXPR.AM3	28707	140.1E	13:18 - 13:51 (annular from 13:33:16 - 13:35:46)
    APSTAR5	28364	138.0E	13:25 - 13:58 (annular from 13:40:27 - 13:41:27)
    
    Note that the shadow moves from East to West in this case contrary to how it 
    moves on the ground. Between 2 and 5 minutes after the end of the (partial 
    phase of) the eclipse (depending on the position) the satellites will enter 
    Earth shadow for one hour. This means that satellite operators will have to  
    rely on battery power for a longer than usual time.
    
    I'd appreciate any reports about this event, particularly the actually 
    observed drop in magnitude of the GEOs.
    
    Gerhard HOLTKAMP
    Darmstadt, Germany
    
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